• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.13 no.4
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• pp.359-365
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• 2002

In this work, a new type of the active array antenna for IMT-2000 base stations by using dual-polarization diversity is proposed and developed. As an element of array antenna, a single micorstrip patch antenna of ${\pm}$ 45$^{\circ}$slanted is designed by obtaining the bandwidth of 1,885 ㎒ to 22,000 ㎒. The polarization isolation between two linearly polarized waves is less than 16 ㏈. The gain of element antenna is more than 7 ㏈i. finally, 2${\times}$8 dual-polarization active array antenna is developed with ElRP of 1,200 W and polarization isolation of 20 ㏈ by placing a low power amplifier at each antenna element.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.7
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• pp.859-866
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• 2010

In this study, microinjection molding process using the newly developed micromold system, namely modularized and sectioned micromold system (MSMS), has been carried out for a replication of multi-level microstructures. The present MSMS consisted of several micromold modules, each having cross-sectional microstructures on the top surface. The micromold modules were precisely fabricated by deep X-ray lithography and subsequent nickel electroforming. By assembling the micromold modules, an MSMS having multi-level microstructures, which could be used as a mold system in micromolding processes, was obtained. In this manner, polymeric multi-level microstructures, such as the triangular prism microstructures on a stepped surface, were successfully replicated by the microinjection molding process.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.05a
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• pp.551-554
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• 2005

This study uses a characteristic function to explain correlations between the objective function and design variables. Analysis of means and table of orthogonal array were carried out. The change of shape of diaphragm, thickness of diaphragm and voice coil weight based on the table of orthogonal array is made. Therefore this study carried to decide shape of diaphragm, voice coil weight and thickness of diaphragm for minimizing 1st natural frequency and maximizing 2nd natural frequency of diaphragm using design of experiments and characteristic function with constraints. we showed improved design factors that minimized 1st natural frequency and maximized 2nd natural frequency of diaphragm.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.05a
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• pp.840-845
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• 2005

This paper presents a robust optimal design method for a periodic structure type of MEMS resonator that is vulnerable to mode localization. The robust configuration of such a MEMS resonator to fabrication error is implemented by changing the regularity of periodic structure. For the mathematical convenience, the MEMS resonator is first modeled as a multi pendulum system. The index representing the measure of mode variation is then introduced using the perturbation method and the concept of modal assurance criterion. Finally, the optimal intentional mistuning, minimizing the expectation of the irregularity measure for each substructure, is determined for the normal distributed fabrication error and its robustness in the design of MEMS resonator to the fabrication error is demonstrated with numerical examples.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.15 no.8 s.101
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• pp.931-938
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• 2005

This paper presents a robust optimal design method for a periodic structure type of MEMS resonator that is vulnerable to mode localization. The robust configuration of such a MEMS resonator to fabrication error is implemented by changing the regularity of periodic structure For the mathematical convenience, the MEMS resonator is first modeled as a multi-pendulum system. The index representing the measure of mode variation is then introduced using the perturbation method and the concept of modal assurance criterion. Finally, the optimal intentional mistuning, minimizing the expectation of the irregularity measure for each substructure, is determined for the normal distributed fabrication error and its robustness in the design of MEMS resonator to the fabrication error is demonstrated with numerical examples.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.887-888
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• 2008

본 논문은 여러 음향신호의 도달각에 기반한 실내측 위성능을 분석한다. 도달각 측정을 위해 송출전력이 같은 총성, 벨소리, 그리고 의사충격음을 사용하였다. 음향 신호는 약 32 평방미터의 실험실에서 한 개의 음원 스피커를 통해 송출되고, 두 쌍의 서로 동기가 맞는 배열 마이크를 통해 수신된다. 수신된 음향신호로부터 한 마이크 쌍 사이의 도달지연시간차가 측정되고, 이로부터 도달각이 산출된다. 끝으로, 음원 스피커의 최종 위치는 도달각의 교점으로 결정된다. 본 논문은 설치한 실험환경에서의 참 도달각과 측정 도달각의 평균절대오차와 측위오차의 상보누적분포를 보이고, 이에 대한 성능특성을 분석한다.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.15 no.7 s.100
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• pp.775-780
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• 2005

This study uses a characteristic function to explain correlations between the objective function and design variables. Analysis of means and table of orthogonal array were carried out. The change of shape of diaphragm, thickness of diaphragm and voice coil weight based on the table of orthogonal array Is made. Therefore this study carried to decide design variables for minimizing 1st natural frequency and maximizing 2nd natural frequency of diaphragm using design of experiments and characteristic function with constraints. we showed improved design variables.

• Proceedings of the KIEE Conference
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• 1999.11d
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• pp.1145-1147
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• 1999

평판전극배열을 이용한 회전구동형 마이크로 액츄에이터의 구동력을 증대시키기 위하여 전극의 형상을 최적화 하였다. 기존 평판구동형 마이크로 액츄에이터의 형상을 변형시켜 반경에 무관하게 전극의 수직간격을 최소간격으로 일정하게 유지함으로서 구동력을 배가시키는 효과를 발생시켰다. 이러한 구동력의 증가는 결국 요구되는 변위를 만족시키면서 고유진동수를 증가시켜 마이크로액츄에이터의 구동성능을 향상시킬 수 있다.

• Journal of the Microelectronics and Packaging Society
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• v.28 no.4
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• pp.57-61
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• 2021

A formation process of indium bump arrays on micro-pillar structures is proposed. The space to form indium bump on the narrow structures can be secured applying the benzocyclobutene (BCB) planarization and its etch-back process. We exhibit a detailed overview of the process steps involved in the fabrication of 320×256 hybrid camera sensor for short-wavelength infrared (SWIR) detection. The shear strength of the BCB, which has undergone the different processes, is extracted by quartz crystal microbalance measurement. The shear strength of the BCB is three orders of magnitude higher than that of the indium bump itself. The measured dark current distribution of the fabricated SWIR camera sensor indicates the suggested process of indium bumps can be useful for embodying highly sensitive infared camera sensors.

• Journal of Institute of Convergence Technology
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• v.1 no.2
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• pp.16-24
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• 2011

The angular electrostatic microactuator using skewed electrode array (SEA) scheme was proposed. The moving and fixed electrodes are arranged to make the driving force perpendicular to the rotating moment of arm. By changing the electrode overlap length, the magnitude of electrostatic force and stable displacement will be changed. In order to optimize the design, electrostatic FE analysis were carried out and the empirical force model was established for SEA. Simulation was performed to make the comparison between conventional actuators and SEA. The proposed SEA generates actuating torque 2 times greater than a comb-drive and stable actuator displacement 40% greater than a parallel plate type actuator. The angular electrostatic microactuator using skewed SEA scheme was designed and fabricated using SoG process.